Among first-time expectant mothers, the risk of vaginal bleeding early in pregnancy is greater for those who have had a medication abortion than for those who have never had any type of abortion, according to a prospective cohort study of Chinese women.' The risk was especially elevated among women whose medication abortion resulted in curettage or complications (odds ratios, 1.6 and 2.0, respectively). The risk of vaginal bleeding early in pregnancy did not differ between women who had had a first-trimester medication abortion and those who had had a first-trimester surgical abortion.
Vaginal bleeding is a sign of a high-risk pregnancy and has been associated with past surgical abortion. To explore whether a similar association exists for nonsurgical abortions, this study compared rates of vaginal bleeding among pregnant women who had had a medication abortion and those who had had a surgical or no abortion.
From 1998 to 2001, investigators recruited women who were 4-16 weeks pregnant from 83 antenatal clinics in Beijing, Chengdu and Shanghai. Women were eligible for the study if they were aged 20-34, had riot given birth before and had previously undergone one first-trimester abortion (surgical or medication) or no abortion. Participants completed questionnaires at enrollment, at 28-30 weeks and at delivery, providing information on their reproductive and medical history, including the current pregnancy. Women's reports of vaginal bleeding were examined overall and for two periods of pregnancy: before enrollment (the first period) and during follow-up (the second period). Log binomial regression analysis was used to calculate the relative risk of vaginal bleeding while controlling for study center, age, income, residence, season at conception and history of chronic disease.
A total of 14,399 women participated of whom 4,841 had had a medication abortion, 4,705 a surgical abortion and 4,853 no abortion. The mean age at recruitment was 26. Most of the women had at least a high school degree; lived in a city; and were industrial or service workers, or farmers. Levels of tobacco and alcohol use, as well as of chronic disease, were low.
On average, women in the three groups enrolled in the study at 10-11 weeks' gestation and had their initial follow-up at 29 weeks. Up to the first follow-up, rates of vaginal bleeding among women with a history of medication abortion, surgical abortion and no abortion were 17%, 17% and 14%, respectively. After adjustments for potential confounders, the risk of vaginal bleeding was significantly higher for women who had had a medication abortion than for those who had had no abortion (relative risk, 1.2). When the relationship between medication abortion and vaginal bleeding was examined according to period of pregnancy, the increased risk was observed only in the first period (1. …